Re: [REGRESSION] "efi: efistub: Convert into static library" and preparation patches

[Maarten Lankhorst <maarten.lankhorst@canonical.com>]

Op 04-09-14 om 09:40 schreef Matt Fleming:
> On Thu, 04 Sep, at 08:47:57AM, Ard Biesheuvel wrote:
>> So how about we:
>> - add ASSERT(_got == _egot, "GOT entries not supported in
>> boot/compressed") to the linker script
>> - #define __nogotentry __attribute__((visibility(hidden))) somewhere
>> in compiler.h or wherever else it belongs
>> - add the __nogotentry qualifiers to each extern that requires it,
>> which is currently:
>> early_serial_base
>> efi_early
>> free_mem_end_ptr
>> free_mem_ptr
>> real_mode
>> - get rid of the fixup code in assembly
>  
> Seems fine to me since it was Peter who introduced the GOT fixup asm
> code in the first place.
>
>> Any idea what the oldest GCC is we should support?
> I'm pretty sure we still support GCC 3.x.x. The symbol visibility
> support was added in GCC 4.x right?
>
gcc 3.3.6 has documented visibility at least.

https://gcc.gnu.org/onlinedocs/gcc-3.3.6/gcc/Function-Attributes.html#Function-Attributes

I couldn't find it in earlier manuals, but grepping through gcc 3.0.4 source code shows that it would appear to be supported there too.

~Maarten